The present invention relates to a ventilated building block construction and to mold components for a machine for making the block.
Currently, typical concrete ventilating blocks are formed with straight, internal passages extending vertically through the block, such that when plural blocks are stacked, a ventilating “chimney” is formed. These and other block constructions are well represented in the patent literature. For example, U.S. Pat. No. 2,137,153 discloses ventilated wall blocks that are stacked vertically in an alternately inverted orientation, establishing both vertical and horizontal vent passageways. In U.S. Pat. No. 7,096,634, a block is disclosed that, when stacked, creates vertical vents or cores. Still other block constructions are disclosed in U.S. Pat. Nos. 1,758,757; 2,624,193; and 4,823,530. A ventilated building block and mold core and stripper shoe components for forming the ventilated building block are described in a commonly-owned U.S. Pat. No. 7,757,451, the entirety of which is incorporated herein by reference.
The block described in the '451 patent includes an elongated center portion flanked by a pair of substantially parallel side walls oriented substantially perpendicularly to the center portion, the center portion having a first vertical wall and a second sloped wall. The sloped wall extends between a relatively thicker bottom wall of the center portion and a relatively thinner top wall. A horizontal shoulder extends across the sloped front wall at a height substantially equal to the height of the side walls, such that the shoulder lies in the same horizontal plane as the upper edges of the side walls. Accordingly, the upper portion of the block assumes a substantially triangular cross-sectional shape.
Another existing design is described in GB 782,754. The building blocks in the GB '754 patent are “precast” (as stated in the patent). Precast products are made by filling a mold with concrete and leaving it for a specific time (usually a minimum of 24 hours), or depending on the design of the item being precast, a couple of days, before stripping it from the mold. The GB '754 design would require anywhere from two to six days before stripping from the mold. The GB '754 design, however, cannot be manufactured on a conventional concrete block machine as the design requires an “upper” and a “lower” core block. The lower core block would prevent or make it impossible to strip the block from the mold as is done on a block machine.